2 Sides to every story

You would think as a 33 year old woman that I would know that every story has 2 sides and not to judge a book by its cover. Yet I find myself in a bad spot. Why do I do this? I know better. Yet I listened to what someone else said and took it for truth. In turn we have hurt a child. How do you make that go away. DH has apologized to the child but he was still very upset with him. Why do people feel the need to talk about something that they know nothing about? Why do we all forget that there are 2 sides to every story. I am so sick of gossip and grown adults acting like they are in high school. I have made a promise to myself that I will never fall into that trap again. From here on out I am done with other peoples drama and gossip.